Daguerreotypes

The American Antiquarian Society's photograph collection includes nearly 230 daguerreotypes. Daguerreotypes, the first commercial form of photography, appeared in America around the year 1839. These were produced by first sensitizing a polished silvered copper plate with iodine vapor, and then exposing the plate to light. The image was developed over hot mercury, fixed, and rinsed. This was a direct positive process, meaning that no negatives were produced, and so each daguerreotype is unique. Daguerreotypes can be easily distinguished from other early photographs by their reflective, mirror-like surface.